Real snow that tiles, not easy. This is not perfect, but an attempt.
Source Atle Mo
More tactile goodness. This time in the form of some rough cloth.
Source Bartosz Kaszubowski
A heavy dark gray base, some subtle noise and a 45-degree grid makes this look like a pattern with a tactile feel to it.
Source Atle Mo
Horizontal and vertical lines on a light gray background.
Source Adam Anlauf
Because I love dark patterns, here is Brushed Alum in a dark coating.
Source Tim Ward
Detailed but still subtle and quite original. Lovely gray shades.
Source Kim Ruddock
Light gray pattern with an almost wall tile-like appearance.
Source Markus Tinner
Just the symbols of the signs of the zodiac distributed in a chequer board-like pattern
Source Firkin
Carbon fiber is never out of fashion, so here is one more style for you.
Source Alfred Lee
To get the tile this is formed from select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
The following repeating website background is colored in a blue gray color and resembles a concrete wall or something similar to it.
Source V. Hartikainen
I love these crisp, tiny, super subtle patterns.
Source Badhon Ebrahim
Here's a bluish gray striped background pattern for use on web sites.
Source V. Hartikainen
Sometimes simple really is what you need, and this could fit you well.
Source Factorio.us Collective
A seamless pattern created from a square tile. To get the tile, select the rectangle in Inkscape and use shift+alt+i.
Source Firkin
A free seamless background image with abstract texture of green "curtain".
Source V. Hartikainen
A pattern formed from a squared tile. The tile can be accessed in Inkscape by selecting the rectangle and using shift-alt-i.
Source Firkin
From a drawing in 'Art Embroidery', M.S. Lockwood and E. Glaister, 1878.
Source Firkin